A piezoelectric/electrostrictive actuator has an advantage that displacement can be controlled in a submicron order with accuracy. In particular, a piezoelectric/electrostrictive actuator, in which a piezoelectric/electrostrictive ceramic sintered body is used as a piezoelectric/electrostrictive body, has advantages such as high electromechanical conversion efficiency, large generating force, high response speed, high durability and less power consumption, in addition to the advantage that displacement can be controlled with accuracy. Thanks to these advantages, the piezoelectric/electrostrictive actuator is used in a head of an inkjet printer, an injector of a diesel engine and the like.
Lead-zirconate-titanate-based piezoelectric/electrostrictive ceramic has been conventionally used as piezoelectric/electrostrictive ceramic for a piezoelectric/electrostrictive actuator. However, there are growing fears that elution of lead from a sintered body may affect global environment, which also leads to a study of alkaline-niobate-based piezoelectric/electrostrictive ceramic.
Patent Literature 1 is a prior art document that describes the invention known to the public through publication related to the present invention. Patent Literature 1 relates to the alkaline-niobate-based piezoelectric/electrostrictive ceramic having a microstructure in which a core particle is enclosed by shell particles.